A very rare fluorescent chemosensor of zinc(II) exhibiting AIEE, ESIPT and TICT: Spectroscopic, crystallographic and theoretical exploration.

The basic systems in this study are HL (1; 1:2 condensation product of 2,6-diformyl-4-ethylphenol and o-anisidine) and its ZnII and CdII complexes of composition [ZnII(LH)Cl2]·CH3OH (2) and [CdII(LH)Cl2] (3), all of which are synthesized and characterized by CHN elemental analyses, single crystal X-ray crystallography, powder X-ray diffraction (PXRD) and fourier transform infrared (FT-IR) spectrum. It has been established from the following experimental and theoretical studies that 1 is a fluorescent turn on sensor of ZnII ion and it exhibits all of excited state intramolecular proton transfer (ESIPT), photoinduced electron transfer (PET), twisted intramolecular charge transfer (TICT) and aggregation induced enhanced emission (AIEE): (i) Detailed absorption and emission (steady state / time resolved) studies in various single solvents, in solvent mixtures, with pH variation, with various single metal ions, with mixtures of metal ions, on varying temperature and on varying viscosity; (ii) dynamic light scattering (DLS) and scanning electron microscopy (SEM) in solvent mixtures; (iii) density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations in ground and excites states of 1-3. It is shown that 1 can be efficaciously applied in inkless writing with the "write - erase - write" facility. The mechanisms/reasons of the observed properties have been addressed. The difference in fluorescence of ZnII and CdII complexes, unusual case of crystal structures of probe and complexes with ZnII and CdII, unusual features in the structures of 2 and 3 as well as a structure-property correlation have been discussed.

Experimental and theoretical investigations on three DyIII4 single molecule magnets: structural and magneto-structural correlations.

The work in this report describes the syntheses, crystal structures, dc/ac magnetic behaviour, and theoretical calculations (both ab initio CASSCF and DFT) of three defect dicubane/planar butterfly type tetradysprosium(III) compounds of compositions [DyIII4L4(µ3-OH)2(carboxylate)2(dmf)2] (carboxylate = formate (1), acetate (2), propionate (3)), where H2L = 2-(2-hydroxy-3-ethoxybenzylideneamino)phenol. In the butterfly type structures, two DyIII centres (Dyb) occupy the body positions while two other (Dyw) units occupy the wing positions. SHAPE analyses reveal that the coordination geometries of the Dyb and Dyw centres, both octacoordinated, are triangular dodecahedron (TDD) and square antiprism (SAPR), respectively. Variable-temperature magnetic susceptibility measurements give an indication of weak antiferromagnetic interactions and variable-field magnetization measurements reveal strong anisotropy in all the three compounds. The variable-temperature/frequency in-phase/out-of-phase AC susceptibility data reveal that all these three compounds are SMMs with two relaxation channels under zero dc field; slow relaxation (SR) and fast relaxation (FR) processes could be assigned to the SAPR (Dyw) and TDD (Dyb) metal centres, respectively. The simulated Ueff and τ0 values are: 49.0 cm-1 and 1.76 × 10-7 s for 1, 30.3 cm-1 and 1.51 × 10-8 s for 2 and 23.4 cm-1 and 9.64 × 10-7 s for 3. Furthermore, ab initio CASSCF/RASSI-SO/SINGLE_ANISO calculations reveal that the ground state of DyIII centres are axial in nature with a dominating contribution from mJ = |±15/2>. The magnetization relaxation occurs via the first excited KD resulting in the large computed blocking barrier of Dyw (SAPR) centres compared to that of the Dyb (TDD) centres which corroborates the experimental measurements. The exchange parameters obtained from DFT calculations are generally in line with those obtained from the fitting of χMT vs. T in POLY_ANISO calculations. Interesting structural and magneto-structural correlations have been found, which are the major outcomes of this investigation.

A metal complex based fluorescent chemodosimeter for selective detection of 2,4-dinitrophenol and picric acid in aqueous media.

This work describes the syntheses, characterization, crystal structures, absorption and emission spectra and DFT calculations of three dizinc(II) compounds of the composition [ZnII2L(µ1,1-N3)(N3)2] (1) [Zn2L'(2,4-dinitrophenolate)2] (2) and [Zn2L'(picrate)2] (3), respectively, (where HL is the 1 : 2 condensation product of 4-ethyl-2,6-diformylphenol and N-methylethylenediamine and H2L' (a diamino-diimino-diphenol system) is a new type of macrocyclic ligand). Compound 1 is water soluble and its aqueous solution exhibits intense fluorescence properties. 2,4-Dinitrophenol (DNP) and picric acid (PA) selectively quench the fluorescence intensity of 1 to a significant extent, revealing that 1 is a fluorescence sensor of DNP and PA. Compounds 2 and 3 were prepared by mixing 1 with DNP and PA. As a huge change in the system (acyclic to macrocyclic) occurs while exhibiting sensing behaviour, it is evident that 1 senses DNP and PA through a chemodosimetric approach in aqueous media. For sensing nitroaromatic compounds, compound 1 acts as (i) a rare chemodosimeter, (ii) a rare metal containing chemodosimeter and (iii) a rare fluorescent chemosensor in aqueous media. Based on the ESI-MS and single crystal X-ray structures, it has been possible to establish a mechanism for the conversion of the acyclic system in 1 to a new type of macrocyclic system in 2 and 3. It has been established from DFT calculations that ground state complexation via charge transfer and IFE can be considered as the major reason for the DNP/PA stimulated strong fluorescence quenching.

A systematic review on the efficacies and therapeutic interventions of homoeopathic medicines in combating viral disorders with implications in the currently undergoinghomoeopathic treatment efforts for SARS-CoV-2 infection (COVID-19)

The prevalence of Severe Acute Respiratory Syndrome-Corona Virus-2 (SARS-CoV-2) has undergone a historic transition from December 2019 to June 2020. Under the current circumstances, SARS-CoV-2 has become a key problem for the public health and economic steadiness of the global fraternity. Based on ample evidences from the global epidemiology of SARS-CoV-2 and MERS-CoV (Middle EastRespiratory Syndrome-Corona virus) scientists and physicians strappingly consider these viruses share structural and functional similarities of selected biologically active enzymes namely, 3CLpro, PLproand RdRp. Ultra-diluted homoeopathic medicine has the legacy to combat infectious as well as viral diseases since last two centuries. Thus, a systematic review on existing antiviral homoeopathic therapies was done in the current study and the need of appropriate clinical validation with proper in vitroas well as in vivostudies prior to make clinical endorsements in treating COVID-19 patients with homoeopathic medicines has been explained. A brief summary of the currently undergoing or recently completed homoeopathic treatments of COVID-19 has also been provided to attract many more similar homoeopathic treatment attempts to combat COVID-19.(AU)

Management of early years of simple and mucopurulent chronic bronchitis with pre-defined Homoeopathic medicines ­ a Prospective Observational Study with 2-Years Follow-Up

Background Simple and mucopurulent chronic bronchitis (SMCB) is characterized by recurrent mucoid or mucopurulent expectoration in absence of localized suppurative disease. This observational open label study was undertaken to evaluate the effects of homeopathic medicine in SMCB. Methods 1902 patients were screened from 07 centres out of which 1305 were excluded. 597 patients were enrolled as per the inclusion and exclusion criteria. A total of 14 pre-defined homeopathic medicines were shortlisted for prescription after repertorizing the pathological symptoms of SMCB. Outcomes were assessed through chronic bronchitis symptom scale (CBSS) and FEV1/ FVC ratio with spirometry for over a period of two years. Appearance of any change (relief/ worse)/ status quo was immediately followed by placebo/ change in dilution/ change in remedy. Statistical analysis was done using SPSS version 20. Results: 532 patients were analyzed based on the intention to treat principle using last observation carry forward method. Mean CBS score reduced from 29.86±4.5 at baseline to 12.33±7.6 at completion of 2 years. Repeated measures ANOVA, at time points 0 (baseline), 3, 6, 9, 12 ,15, 18, 21 and 24 months, showed significant reduction in CBS scores [Wilk's Lambda 0.104, F=564, df 524; p=00001]. The FEV1 and FEV1/FVC was maintained within normal limits. 86% prescriptions included Lycopodium, Arsenicum album, Pulsatilla, Phosphorus, Stannum metallicum, Calcarea carbonica, Silicea, Bryonia alba. Conclusion: The result suggests effectiveness of homeopathic treatment in early years of SCMB patients. Controlled trials are warranted. (AU)